Referring to FIG. 1, a prior art yarn cylinder illustrated in U.S. Pat. No. 7,114,227 assigned to the inventor and applicant of the present invention is disclosed. As conveyed by the drawings, the prior art improves the circumferential length of the trench 1 and, furthermore, postures the teeth 10 in the trench 1 at differing angular orientations; specifically, the teeth 10 are disposed at varying inclinations along the two lateral walls of the trench 10 and, furthermore, the teeth 10 are in a crisscross formation on the two lateral walls; as such, the longer circumferential length of the trench 10 and the contrastive skewing of the teeth 10 effectively increases yarn end snagging capacity. When yarn a is wound in the trench 1, it is caught on plurality of teeth 10 arrayed in the crisscross formation, the many differing angles of the plurality of teeth 10 in the crisscross formation situating the teeth 10 for interlocking utilization such that the yarn cylinder trench 1 not only better accommodates and binds the end of the yarn, but at the same time the interlocking characteristics secures the yarn more effectively.
However inventor find finds that the prior art can still be improved so that the yarns can be clamped in the trench effectively.